A solid sphere of radius R is placed at a height of 36 cm on a 15 slope. It is released and rolls, without slipping, to the bottom.

A solid sphere of radius R is placed at a height of 36 cm on a 15∘ slope. It is released and rolls, without slipping, to the bottom.

From what height should a circular hoop of radius R be released on the same slope in order to equal the sphere's speed at the bottom?